I am setting up a 10 gallon tank and I am using two light fixtures that I have sitting around from a couple of old 20 gallon tanks. I will end up with 45 watts but it will be from 3 15 watt bulbs.

My question is would this be considered high light since it is from the 15 watt bulbs and not one compact flourescent?

Would this be enough light to make it worth my while to use my hagen CO2 system? I have had a bad experience with this before as I had two algae blooms because I used this while I only had 1.5 WPG on my 20 gallon.

Extra CO2 isn't gonna cause an algae bloom...something else was outta whack in the 20 gallon..and even 1.5wpg is enough for CO2 to start to make a difference...mostly in bushier plant growth. Algae blooms come from excess nitrates and phosphates...sometimes iron, but not CO2....in fact high light tanks without CO2 usually have algae problems that are only solved by CO2 injection.

Yes, you do have 4.5wpg with 3x15w normal fluorescent tubes. Since those 3 strips should end up covering the entire top, you should have really even lighting, and enough to call it 'high light'. You'll definitely need some CO2 injection, and fertilizing will be 2-3 times a week.

Extra CO2 isn't gonna cause an algae bloom...something else was outta whack in the 20 gallon..and even 1.5wpg is enough for CO2 to start to make a difference...mostly in bushier plant growth. Algae blooms come from excess nitrates and phosphates...sometimes iron, but not CO2....in fact high light tanks without CO2 usually have algae problems that are only solved by CO2 injection.

Yes, you do have 4.5wpg with 3x15w normal fluorescent tubes. Since those 3 strips should end up covering the entire top, you should have really even lighting, and enough to call it 'high light'. You'll definitely need some CO2 injection, and fertilizing will be 2-3 times a week.

I agree and agree with malkore. Your tank is high light, but from 15W bulbs, you only have 15W intensity - this is a lesser factor and shouldn't be concerned with.

The algae problem could have been from other factors. You must test for phosphates and nitrates to properly diagnose any algae bloom.

I never could figure out why I had the algae blooms before. I tested my tank frequently before both blooms and my nitrates were never above 10ppm and my phosphates were never above 0.25 mg/L. They only common denominator I could think of was the CO2 unit. I guess I will never know what happened before. I am glad to learn that it had nothing to do with the CO2.

I never could figure out why I had the algae blooms before. I tested my tank frequently before both blooms and my nitrates were never above 10ppm and my phosphates were never above 0.25 mg/L. They only common denominator I could think of was the CO2 unit. I guess I will never know what happened before. I am glad to learn that it had nothing to do with the CO2.

Well there is your likely problem. Over 10ppm nitrate and only .25ppm phosphate. Nitrates and phosphates are sopposed to be at a 10:1 ratio. So get your nitrates down to 2.5ppm...or better yet raise your phosphate to .5ppm and get your nitrates to 5ppm.

We all tend to run our levels differently. I usually have 20ppm of nitrate, and keep my phosphate at 1.0ppm. I get a little bit of green spot algae, but even that's going away after changing my source of trace fertilizer.

My suggestion, keep phosphates between .5 and 1.0ppm and nitrates between 5 and 15ppm proportionately, and you shouldn't have the algae issues. Play around with the levels, but keep them stable for 2-3 weeks at a time before deciding whether the level is good or not. It takes several days for a change in your routine to affect the plants.

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